Sprockets, roller chain, metric engage chains in many different power transmission and conveyor systems. Chain drives are often used as economic, reliable drive systems for long running, continuous drive applications with limited shock and torque loads. Metric sprockets are classified according to ISO number designations. Sprockets engage chains in many different power transmission and conveyor systems. Chain drives are often used as economic, reliable drive systems for long running, continuous drive applications with limited shock and torque loads. English sprockets are classified according to ANSI number designations.